arXiv subjects

S. P. Lukyanets

Publications and source records attributed to S. P. Lukyanets.

9 recordsLinked to original sources

arXiv2026

Nonequilibrium protection effect and spatial localization of noise-induced fluctuations: Quasi-one-dimensional driven lattice gas with partially penetrable obstacle

We consider a nonequilibrium transition that leads to the formation of nonlinear steady-state structures due to the gas flow scattering on a partially penetrable obstacle. The resulting nonequilibrium steady state (NESS) corresponds to a two-domain gas structure attained at certain critical parameters. We use a simple mean-field model of the driven lattice gas with ring topology to demonstrate that this transition is accompanied by the emergence of local invariants related to a complex composed of the obstacle and its nearest gas surrounding, which we refer to as obstacle edges. These invariants are independent of the main system parameters and behave as local first integrals, at least qualitatively. As a result, the complex becomes insensitive to the noise of external driving field within the overcritical domain. The emerged invariants describe the conservation of the number of particles inside the obstacle and strong temporal synchronization or correlation of gas states at obstacle edges. Such synchronization guarantees the equality to zero of the total edge current at any time. The robustness against external drive fluctuations is shown to be accompanied by strong spatial localization of induced gas fluctuations near the domain wall separating the depleted and dense gas phases. Such a behavior can be associated with nonequilibrium protection effect and synchronization of edges. The transition rates between different NESSs are shown to be different. The relaxation rates from one NESS to another take complex and real values in the sub- and overcritical regimes, respectively. The mechanism of these transitions is governed by the generation of shock waves at the back side of the obstacle. In the subcritical regime, these solitary waves are generated sequentially many times, while only a single excitation is sufficient to rearrange the system state in the overcritical regime.

cond-mat.stat-mech↗

arXiv2021

Modeling and Controlling the Spread of Epidemic with Various Social and Economic Scenarios

We propose a dynamical model for describing the spread of epidemics. This model is an extension of the SIQR (susceptible-infected-quarantined-recovered) and SIRP (susceptible-infected-recovered-pathogen) models used earlier to describe various scenarios of epidemic spreading. As compared to the basic SIR model, our model takes into account two possible routes of contagion transmission: direct from the infected compartment to the susceptible compartment and indirect via some intermediate medium or fomites. Transmission rates are estimated in terms of average distances between the individuals in selected social environments and characteristic time spans for which the individuals stay in each of these environments. We also introduce a collective economic resource associated with the average amount of money or income per individual to describe the socioeconomic interplay between the spreading process and the resource available to infected individuals. The epidemic-resource coupling is supposed to be of activation type, with the recovery rate governed by the Arrhenius-like law. Our model brings an advantage of building various control strategies to mitigate the effect of epidemic and can be applied, in particular, to modeling the spread of COVID-19.

physics.soc-ph↗

arXiv2020

Epidemic-Driven Collapse in a System with Limited Economic Resource. II

We consider a possibility of socioeconomic collapse caused by the spread of epidemic. To this end, we exploit a simple SIS-like (susceptible-infected-susceptible) model with negative feedback between the infected population size and a collective economic resource associated with the average amount of money or income per economic agent. The coupling mechanism in such a system is supposed to be of activation type, with the recovery rate governed by the Arrhenius-like law. In this case, economic resource formally plays the role of effective market temperature and the minimum level of resource consumption is associated with activation energy. Such a coupling can result in the collapsing effect opposite to thermal explosion, so that the epidemic could ultimately drive the system to a collapse at nonzero activation energy because of the limited resource. In this case, the system can no longer stabilize and return to the stable pre-epidemic state or a poorer post-epidemic state. We demonstrate that the system's collapse can partially be mitigated by external subsidies meaning constant resource inflow from some external source or by means of debt interpreted as a negative resource. We also consider a simple quarantine scenario and show that it can lead to different socioeconomic outcomes, depending on initial resource (market temperature) and the minimum level of resource consumption (activation energy).

physics.soc-ph↗

arXiv2020

Collective wake-mediated interactions in lattice fluids: Effects of strong local force fluctuations stimulated by impurity disorder

The perturbation of a medium field (a particle wake) determines the Stokes drag on the particle itself. Besides, it affects the motion of other particles, inducing non-equilibrium correlations between them. We study the induced non-equilibrium correlations and forces, acting on constituent particles of the bunch or cluster of impurities exposed to a gas stream. Such induced correlations exhibit many striking features that are determined by the properties of particle bunch collective scattering in a medium. The characteristics of collective scattering are determined by the structure of the bunch itself, that is associated with scattering on inhomogeneities, i.e., on fluctuations of the number of particles (scatterers) in a correlation volume. This is well-known, e.g., in optics and have been shown for gas scattering in our recent work [1]. In particular, a random cluster of impurities experiences much stronger Stokes drag than a regular one. Inhomogeneity of the cluster also determines the presence of giant local fluctuations of the scattered field inside a cluster, that was shown for gas stream scattering in [1]. This, in turn, should lead to strong local fluctuations of induced gradient forces inside the cluster, which can determine its stability. Moreover, the description of a cluster in terms of effective parameters (penetration index, effective diffusion coefficient, etc.) brakes down due to the presence of such fluctuations.

cond-mat.stat-mech↗

arXiv2020

The Epidemic-Driven Collapse in a System with Limited Economic Resource

We consider a possibility of socioeconomic collapse caused by the spread of epidemic in a basic dynamical model with negative feedback between the infected population size and a formal collective economic resource. The epidemic-resource coupling is supposed to be of activation type, with the recovery rate governed by the Arrhenius-like law and resource playing the role of temperature. Such a coupling can result in the collapsing effect opposite to thermal explosion because of the limited resource. In this case, the system can no longer stabilize and return to the stable pre- or post-epidemic states. We demonstrate that such a collapse can partially be mitigated by means of a negative resource or debt.

physics.soc-ph↗

arXiv2018

Effects of Collectively Induced Scattering of Gas Stream by Impurity Ensembles: Shock-Wave Enhancement and Disorder-Stimulated Nonlinear Screening

We report on specific effects of collective scattering for a cloud of heavy impurities exposed to a gas stream. Formation is presented of a common density perturbation and shock waves, both generated collectively by a system of scatterers at sudden application of the stream-inducing external field. Our results demonstrate that (i) the scattering of gas stream can be essentially amplified, due to nonlinear collective effects, upon fragmentation of a solid obstacle into a cluster of impurities (heterogeneously fractured obstacle); (ii) a cluster of disordered impurities can produce considerably stronger scattering accompanied by enhanced and accelerated shock wave, as compared to a regularly ordered cluster. We also show that the final steady-state density distribution is formed as a residual perturbation left after the shock front passage. In particular, a kink-like steady distribution profile can be formed as a result of shock front stopping effect. The possibility of the onset of solitary diffusive density-waves, reminiscent of precursor solitons, is shown and briefly discussed.

cond-mat.stat-mech↗

arXiv2016

Attraction/repulsion switching of non-equilibrium depletion interaction caused by blockade effect in gas of interacting particles. II

The effect of concentration-dependent switching of the non-equilibrium depletion interaction between obstacles in a gas flow of interacting Brownian particles is presented. When increasing bath fraction exceeds half-filling, the wake-mediated interaction between obstacles switches from effective attraction to repulsion or vice-versa, depending on the mutual alignment of obstacles with respect to the gas flow. It is shown that for an ensemble of small and widely separated obstacles the dissipative interaction takes the form of induced dipole-dipole interaction governed by an anisotropic screened Coulomb-like potential. This allows one to give a qualitative picture of the interaction between obstacles and explain switching effect as a result of changes of anisotropy direction. The non-linear blockade effect is shown to be essential near closely located obstacles, that manifests itself in additional screening of the gas flow and generation of a pronounced step-like profile of gas density distribution. It is established that behavior of the magnitude of dissipative effective interaction is, generally, non-monotonic in relation to both the bath fraction and the external driving field. It has characteristic peaks corresponding to the situation when the common density "coat" formed around the obstacles is most pronounced. The possibility of the dissipative pairing effect is briefly discussed. All the results are obtained within the classical lattice-gas model.

cond-mat.stat-mech↗

arXiv2015

Switching of non-equilibrium depletion force caused by blockade effect

The concentration-dependent switching of the non-equilibrium depletion forces between obstacles in an interacting Brownian gas flow is presented. It is shown that this switching is caused by the blockade effect for the gas particles. With increasing equilibrium gas concentration, the gas particles blockade causes the obstacle wake inversion (trace profile turn-over) that, in turn, leads to the change of sign of dissipative interaction. Some non-linear effects such as formation of a cavity-like sparse wake behind the obstacle and the dissipative pairing effect are discussed briefly. The results are obtained within the lattice gas model in the mean-field approximation.

cond-mat.stat-mech↗

arXiv2012

Induced long-time correlations in a two-component lattice gas

The distinguishability of at least two species of particles in the classical lattice gas with no interactions except hard-core exclusion entails additional interparticle correlations. A nonlinear mixing flow appears and manifests itself most pronounced in the case of significant difference between mobilities of species. It may result in the induced correlations for the slow component mediated by the fast one. In the quasi-one-dimensional case, the long-time correlations are demonstrated to take place in the slow component, that is similar to the hydrodynamic correlations between colloidal particles. In the adiabatic approximation, these correlations may come into play only in the non-equilibrium case with the flow of the fast component present in the system.

cond-mat.stat-mech↗